The present disclosure relates to a support device, in particular to a device of the mattress type for supporting a body, in particular the body of a patient, and comprising a structure made up, at least in part, of a plurality of inflatable elements or cells suitable for being inflated with a fluid, in particular for being inflated with air.
The present disclosure relates particularly, but in a non-limiting manner, to support devices that are conventionally used in healthcare beds and in wheelchairs or other healthcare seats, and that are made up of inflatable elements, generally in the form of substantially cylindrical sausage-shaped tubes that extend transversely relative to the longitudinal direction of the mattress and that are disposed side-by-side in the longitudinal direction of the mattress.
In a support device of this type, which can be used, in particular, as a mattress, each inflatable element is generally provided with an air feed orifice and with an air discharge orifice, which orifices are equipped with or communicate in a substantially leaktight manner with at least one air feed means, e.g. via a solenoid valve that is itself connected to a pneumatic control device for controlling inflation of the inflatable elements of the mattress and for regulating the air pressures inside the elements.
In practice, in order to fill or inflate one of the inflatable elements of the support device, air is fed into the element via its feed orifice until the necessary pressure is reached inside the inflatable element. Conversely, in order to empty or deflate one of the inflatable elements, or in order to adjust the pressure inside the element, the feed orifice is kept closed and the air is discharged via the discharge orifice provided for that purpose, and in some instances, also provided with a solenoid valve that is also controlled by the pneumatic control device for controlling inflation.
Support devices of this type are used as mattresses for patient care because they make it possible to distribute appropriately the interface pressure, i.e. the pressure exerted locally by each point of the body on the surface of the mattress, as a function of the morphology and of the position of the patient.
In particular, such mattresses make it possible, as a function of the number of inflatable elements implemented, to control individually the pressure, and therefore, the filling of the inflatable elements in different zones of the mattress so as to procure an appropriate distribution of interface pressure engaging each portion of the patient's body, and so as to avoid or reduce the risks of bedsores forming in zones of the body that are at risk, such as the zone of the sacrum and the zone of heels, for example.
In principle, ideal patient comfort and optimum blood circulation for avoiding bedsore formation or for reducing local pain in certain zones of the body that bear against the mattress are obtained when the bearing points of the body are redistributed over the surface of the mattress, i.e. when the pressure exerted by the various zones of the body on the mattress (which pressure is referred to as the “interface pressure”) is substantially identical at all of the points of the surface of body that are in contact with the mattress and if, in addition, the surface area of the body that is contact with the mattress is as large as possible, which requires the degree to which the inflatable elements of the mattress are inflated under the various portions of the body to be adapted to control the depth to which the body penetrates into the various zones of the mattress.
For this purpose, the air pressures inside the inflatable elements are distributed by controlling the filling/emptying of the elements in accordance with certain pre-established calculations based on, and as a function of, measurements taken with sensors in, on, or below the mattress, depending on the type of sensors implemented.
Such sensors are known to the person skilled in the art and can measure the pressure exerted by the patient's body or the depth to which the patient's body penetrates into the given compartments of the mattress, as described, for example, in the Applicant's European Patent EP 0 676 158 and in the Applicant's European Patent EP 1 056 372 which are hereby incorporated by reference herein.
Controlling and regulating filling/emptying of the inflatable elements via solenoid valves also makes it possible to obtain support devices that operate in an “alternating-pressure mode” in which certain inflatable elements of the support device that are uniformly distributed along the length thereof are inflated and deflated simultaneously and in alternation. For example, one in every two elements, or two in every three elements, or indeed one in every four elements, are deflated and re-inflated, and then the elements adjacent to the previously deflated and re-inflated compartments are deflated and re-inflated.
Thus, each inflatable element of the support device is deflated/re-inflated in succession, one after another, thereby creating a sort of wave moving back and forth in the longitudinal direction of the support device and relieving the interface pressure locally, thereby locally facilitating blood circulation through the soft tissue at the interface with the surface of the support device.
Currently, support devices, in particular mattresses, incorporating such inflatable elements are frequently made up of a first layer of geometrical shape that is kept unchanging by construction and that is generally constituted by an air mattress having a casing that is not elastic, or by a layer of foam, this first layer being of thickness that is generally constant over the entire length of the mattress, forming a “bottom” mattress on which a second layer or “therapeutic” mattress is placed that is formed by juxtaposing inflatable elements that are welded (e.g., heat-sealed) or otherwise bonded together, and that are in the general shape of substantially cylindrical sausage-shaped tubes or cells extending in a direction perpendicular to the longitudinal direction of the mattress. Each of the zones of the therapeutic mattress is provided with solenoid valves and with pipes or tubes adapted to be connected to an inflation and regulation device that is generally independent from the mattress. The foam bottom mattress and the therapeutic mattress formed of inflatable cells are enclosed in a cover that is specially adapted to enable the inflatable sausage-shaped tubes of the therapeutic mattress to be fed and emptied via its pipes connected to an accompanying inflation and regulation device.
Such mattresses of structure that is at least partially inflatable make it possible to assist in preventing, and in providing effective and increased treatment of bedsores and of other lesions or pain that develop as a result of patients being kept in the recumbent position and almost immobile for prolonged periods in hospital beds, in particular by implementing cycles of alternately inflating and deflating the cells of the therapeutic mattress and by using inflation pressures for the cells that differ as a function of the various support zones for supporting the patient's body.
However, since each patient has morphology, height, weight, and pathologies that differ from those of another patient, it is desirable to improve further the comfort of inflatable-cell mattresses, and in particular their capacities for adapting the support procured by the mattress in the various zones of the patients' bodies as a function of the physical and pathological parameters of the patients, as mentioned above, and of the positions of the patients on the mattresses, in particular when going from a recumbent position to a sitting position on the mattress, for example.
In addition, currently existing inflatable-cell mattresses may sometimes also suffer from two other main drawbacks.
Air cells that are too wide give rise, for example, to large gaps in alternating-pressure mode and suffer from the drawback of letting the patient “sink down” between the air cells, mainly in the zone for supporting the sacrum. As a result, the support imparted by that zone is no longer optimized, and there is a risk of the patient feeling discomfort by bearing against the bottom layer of the mattress whose texture is different from the texture of the therapeutic mattress.
The same can also apply in particular in the zone for supporting the heels, where the very small bearing surface areas of the heels can find themselves between air cells, with the same consequences as described above.
In addition, in the event of untimely deflation of the air cells, the therapeutic mattress no longer imparts any support wherever the bottom mattress is absent and is therefore not serving as a backup support surface, in which case the risk of bedsores is also increased for the patient.